Abstract Comet 67P/Churyumov-Gerasimenko was a target of the Rosetta space mission. Worldwide ground-based observations were conducted simultaneously with the mission’s operation in 2015-2016 using all available facilities and various methods. In this work, we present the results of observations during the comet’s subsequent apparition in 2021-2022. Photometric monitoring observations were carried out with the 2-m Liverpool Telescope using SDSS filters. The dataset spans 120 days before and 220 days after perihelion. The averaged colour values for g − r, r − i, and i − z are 0.58, 0.266, and 0.06, respectively. Mean value of normalised spectral gradient S′(g − r) is 8 per cent per 1000 Å. Neither the colour indices nor the spectral gradient showed any dramatic changes throughout the duration of our observations. The comet demonstrated perihelion asymmetry in activity. We estimated dust activity levels using the Afρ parameter. The Afρ value in the r-sdss filter reached approximately 250 cm nearly two months after perihelion passage. The maximum of the dust activity level shifted farther from perihelion than in the previous passage. Comparing the peak activity of the two latest apparitions revealed that the 2021-2022 passage exhibited a lower maximum level, whereas at larger distances from perihelion, the opposite trend may be observed.
Shubina et al. (Fri,) studied this question.
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